Patent application title: ARTIFICIAL TURF INFILL

Abstract:

An artificial turf infill comprising an organic material including ground
walnut shells having each organic particle completely coated with an
anti-microbial agent. Water-retaining particles are added to the infill
ranging between 0 and 60% of total weight of the mixture. Synthetic,
ecologically-safe resilient granules preferably between approximately 20%
and 25% by weight may be added to the infill to improve shock attenuation
(lower G-max) properties of the infill mixture. The water-retaining
particles and synthetic resilient granules within the infill are
completely coated with the anti-microbial agent.

Claims:

1. An artificial turf infill comprising:organic particles; andan
anti-microbial agent applied to cover each of said organic particles to
prevent decomposition of said organic particles.

5. The artificial turf infill as recited in claim 1 wherein said particles
comprise a sieve-size in the range of 8 to 50.

6. The artificial turf infill as recited in claim 1 wherein said infill
comprises water retaining particles ranging between 0 and 60% of the
total weight of said infill, each of said water retaining particles being
covered with said anti-microbial agent.

8. The artificial turf infill as recited in claim 6 wherein said water
retaining particles comprise one of a group consisting of vermiculite and
calcined clay.

9. The artificial turf infill as recited in claim 1 wherein said infill
further comprises ecologically-safe, resilient synthetic granules, coated
with said anti-microbial agent, to improve shock attenuating qualities of
said infill when installed in said artificial turf.

10. The artificial turf infill as recited in claim 6 wherein said infill
further comprises ecologically-safe, resilient synthetic granules, coated
with said anti-microbial agent, to improve shock attenuating qualities of
said infill when installed in said artificial turf.

11. The artificial turf infill as recited in claim 9 wherein said infill
comprises a percentage by weight of resilient synthetic granules in the
range between 0 and 75%.

13. An artificial turf infill prepared by the process of:grinding an
organic hard material to form particles; andspraying an anti-microbial
agent to completely coat each of said particles of said ground organic
material thereby preventing decomposition of said ground organic
particles.

14. The process as recited in claim 13 wherein said step of grinding an
organic hard material comprises the step of grinding walnut shells.

15. The process as recited in claim 14 wherein said step of spraying an
anti-microbial agent to completely coat each of said particles comprising
said ground walnut shells comprises the step of pre-coating said ground
walnut shells with a resin primer prior to spraying said anti-microbial
agent.

16. The process as recited in claim 13 wherein said step of grinding an
organic hard material to form particles comprises the step of grinding
one of a group consisting of coconut shells, pecan shells, peanut shells,
corn cobs, and olive stones.

17. The process as recited in claim 13 wherein said process comprises the
step of grinding said particles to a sieve-size in the range of 8 to 50.

18. The process as recited in claim 13 wherein said process comprises the
step of adding water retaining particles to said infill ranging between 0
and approximately 60% of the total weight of said infill prior to
spraying said infill with said anti-microbial agent.

19. The process as recited in claim 13 wherein said process further
comprises the step of adding an ecologically-safe, resilient synthetic
granules to said infill to improve shock attenuating properties of said
infill prior to spraying said infill with said anti-microbial agent.

20. The process as recited in claim 19 wherein said step of adding
ecologically-safe, resilient synthetic granules to said infill comprises
the step of adding a thermoplastic elastomer.

21. Use of particles of a ground organic material, each of the particles
coated with an anti-microbial agent to prevent decomposition of said
particles, as infill material in an artificial turf system.

22. The use of particles as recited in claim 21 wherein said ground
organic material comprises ground organic hard shells or pit material.

23. The use of particles as recited in claim 21 wherein said ground
organic material comprises walnut shells.

24. The use of particles as recited in claim 21 wherein said ground
organic material comprises one of the group consisting of coconut shells,
pecan shells, peanut shells, corn cobs, and olive stones.

25. Use of particles of a ground organic material, each of the particles
coated with an anti-microbial agent, as infill material in artificial
grass.

26. The use of particles as recited in claim 25 wherein said ground
organic material comprises ground organic hard shells or pit material.

27. The use of particles as recited in claim 25 wherein said ground
organic material comprises walnut shells.

28. The use of particles as recited in claim 25 wherein said ground
organic material comprises one of the group consisting of coconut shells,
pecan shells, peanut shell, corn cobs, and olive stones.

29. The use of particles of a ground organic material, each of the
particles coated with an anti-microbial agent, as recited in claim 21
further including water retaining particles, coated with said
anti-microbial agent, varying between 0 and 60% of the total weight of
said infill, as infill material in said artificial turf system.

30. The use of particles of a ground organic material, each of the
particles coated with said anti-microbial agent as recited in claim 29
wherein said water retaining particles comprise one of the group
consisting of pozzolon, vermiculite and calcined clay, as infill material
in said artificial turf system.

31. The use of particles of a ground organic material, each of the
particles coated with an anti-microbial agent as recited in claim 21 and
further including synthetic, ecologically-safe resilient granules coated
with said anti-microbial agent preferably between approximately 20% and
25% by weight to improve shock activation properties, as infill material
in said artificial turf system.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]This invention relates generally to artificial turf playing surfaces
for athletic games and, in particular, to an infill particulate material
placed in and between artificial blades of grass.

[0003]2. Description of the Prior Art

[0004]Prior embodiments of artificial turf, commonly called "infilled
turf" as disclosed in U.S. Pat. No. 4,337,283, issued Jan. 29, 1982 to
Frederick T. Haas, Jr. and in U.S. Pat. No. 5,976,645 issued Nov. 2, 1997
to Daniel A. Daluise et al. represent a great improvement over the
original short-pile artificial playing surfaces in that they reduce
abrasiveness, increase shock attenuation, improve response to foot and
ball actions, and have an improved appearance.

[0005]These "infilled" turf systems incorporate an infill (particulate
placed in and between the artificial grass blades), consisting of a
mixture of rubber and sand or rubber, only. Because of its lower cost,
the rubber used is almost exclusively derived from recycled tires. The
sand component invariably contains silica. In recent years, much concern
has been raised with regard to the environment, ecological, health and
safety hazards of these infill components.

[0006]Rubber contains many problematic synthetic chemicals, such as
polycyclic aromatic hydrocarbons (PAHs) and toxic heavy metals. A number
of these PAHs, such as benzopyrene, are known carcinogens. Others, such
as lead, zinc and cadmium, also could be harmful to the environment, if
introduced through run-off from infilled artificial turf fields. Silica
is also a known carcinogen and it is associated with silicosis and other
respiratory harm. In addition, any of these materials, when installed as
a conventional infill matrix, are believed to promote microbe growth,
such as bacteria, fungi and mold. These concerns have promoted
development of "safer" infill material alternatives such as thermoplastic
elastomers (TPEs) or ethylene-propylene diene monomer (EPDM). Because
these synthetic materials are not generally available in recycled form,
their cost is a deterrent to their use and, because of cost, they are
usually mixed with sand to achieve the full-depth of infill required, at
a reasonable cost. Such systems, therefore still suffer the concerns
associated with silica sand, including the "Petri-dish effect" on microbe
growth.

[0007]To circumvent the problems of cost, synthetic inclusion, and sand
inclusion, some naturally occurring organic materials have been used.
Chief among these has been ground coconut shell. However, coconut shell
and other natural organics carry their own set of concerns. Since organic
materials provide nutrients for microbes, they not only provide support
for microbial growth, but also are susceptible to decomposition actuated
by those same microbes.

[0008]Other prior art references include U.S. Patent Application
Publication No. US2007/0049694 Published Mar. 1, 2007, Inventor Michael
Roch, et al. entitled "Use of a Vulcanized Thermoplastic Elastomer or
Styrene-Ethylene-Butadiene-Styrene Polymer Infill Material in Artificial
Turf System" which discloses the use of, for example, a vulcanized
thermoplastic elastomer in artificial turf systems particularly for
football fields. However, this use of a vulcanized thermoplastic
elastomer carries its own set of problems including high cost for the
intended purpose, the perception of ecological risks associated with
synthetic chemicals, and the necessity to mix with sand to reduce cost
and achieve the proper "feel" and surface response.

[0009]Also, U.S. Patent Application Publication No. US2006/0100342
published May 11, 2006, Inventor Victor Jensen, entitled "Coated Sand
Grains" discloses a particular material consisting of sand grains coated
with a thermoplastic polymer to provide a loose material with properties
suitable for use as a surfacing composition, in particular for sports
surfaces such as a field of artificial grass. However, this product
carries the risk of ecologically harmful run-off from the surface applied
thermoplastic polymers, a very high specific gravity and bulk-density,
which greatly increases the weight of material required for a given depth
of infill thus increasing total material cost and dramatically increasing
freight costs, and the negative features of sand whereby it compacts over
time thus inhibiting drainage and reducing shock attenuation.

[0010]Further, U.S. Patent Application Publication No. US 2006/0172092,
published Aug. 3, 2006, inventor Christopher Tetrault, entitled
"Synthetic Turf Having Cooling Layer" discloses a synthetic turf for
landscaping and athletic fields having a cooling layer to substantially
dissipate heat buildup common with synthetic turf. A particular infill is
introduced between grass-like filaments of the synthetic turf covering
comprising a super absorbent material such as polyacrylamide or
polyacrylate. The hydrophilic material swells in water or other
introduced liquids to about 200 to about 400 times its density. However,
this design carries the disadvantage of changing dimension (swelling) in
water, which changes the surface configuration by increasing infill
depth. This results in a change in surface performance characteristics,
as well as a change in surface response or "feel". In addition, the
synthetic chemicals still carry the perceived ecological risks associated
with exposure to synthetic chemicals. Cost is also high for the intended
use in athletic surfaces.

[0011]U.S. Pat. No. 6,818,274, issued Nov. 16, 2004 to Mark E. Buch, et
al, entitled "Artificial Turf System Using Support Material For Infill
Layer" discloses an artificial turf system comprising an infill of
particulate material disposed between turf fibers upon an upper layer of
turf backing. The infill layer may include a base course of ceramic
support material. A top course may be resilient particles and provide
cushioning or shock absorption. However, this system is relatively high
in cost for the intended use, requires the incorporation of "resilient
particles" which are potentially environmentally and ecologically unsafe,
and does not address the microbial growth problem.

SUMMARY OF THE INVENTION

[0012]Accordingly, it is therefore an object of the present invention to
provide an organic and/or inorganic artificial turf infill that is free
of any synthetic chemicals, free of silica sand,
environmentally-friendly, ecologically-safe, and non-supportive of
microbial growth, and therefore resistant to decomposition.

[0013]It is another object of this invention to provide an artificial turf
"infill" that is a naturally occurring organic hard material such as
walnut shell, peanut shell, corn cob, pecan shell, or hard pit material
such as olive stone, but the preferred material is walnut shell.

[0014]It is yet another object of this invention to provide an organic
substance mixed with the natural inorganic material that absorbs and
retains water, such as pozzolan, vermiculite, perlite, cork, or calcined
clay, with the preferred inorganic additive being pozzolon because of its
specific gravity being similar to walnut shells.

[0015]It is a further object of this invention to provide a shock
attenuating matrix sufficient to meet the requirement consistent with its
use in an athletic surface, landscape grass or play-area safety surface.

[0016]It is a further object of this invention to provide an infill
material with higher albedo and increased water absorption and retention
capacity, thus increasing the capability to reduce surface temperature of
the artificial turf through evaporative cooling.

[0017]It is yet another object of this invention to prevent microbial
propagation in the infill matrix to not only prevent bacteria, fungi and
mold growth but also to inhibit the decomposition of the organic
materials actuated by microorganisms.

[0018]These and other objects are further accomplished by an artificial
turf infill comprising organic particles and an anti-microbial agent
applied to cover each of the organic particles to prevent decomposition
of the organic particles. The organic particles preferably comprise
ground walnut shells, and the organic particles may comprise one of a
group consisting of ground coconut shells, ground pecan shells, ground
peanut shells, ground corn cobs, and olive stones. The organic particles
comprise a sieve-size in the range of 8 to 50. The infill comprises water
retaining particles ranging between 0 and 60% of the total weight of said
infill, each of the water retaining particles being covered with the
anti-microbial agent. The water retaining particles comprise pozzolon, or
may comprise one of a group consisting of vermiculite and calcined clay.
The infill further comprises ecologically-sate, resilient synthetic
granules, coated with the anti-microbial agent, to improve shock
attenuating qualities of the infill when installed in the artificial
turf.

[0019]The objectives are further accomplished for preparing the artificial
turf infill by the process of grinding an organic hard material to form
particles, and spraying an anti-microbial agent to completely coat each
of the particles of the ground organic material thereby preventing
decomposition of the ground organic particles. The step of grinding an
organic hard material comprises the step of grinding walnut shells. The
step of grinding an organic hard material to form particles comprises the
step of grinding one of a group consisting of coconut shells, pecan
shells, peanut shells, corn cobs, and olive stones. The process comprises
the step of grinding the particles to a sieve-size in the range of 8 to
50. The process comprises the step of adding water retaining particles to
the infill ranging between 0 and approximately 60% of the total weight of
the infill prior to spraying the infill with the anti-microbial agent.
The process further comprises the step of adding an ecologically-safe,
resilient synthetic granules to the infill to improve shock attenuating
properties of the infill prior to spraying the infill with the
anti-microbial agent. The step of adding ecologically-safe, resilient
synthetic granules to the infill comprises the step of adding a
thermoplastic elastomer.

[0020]The objectives are further accomplished by the use of particles of a
ground organic material, each of the particles coated with an
anti-microbial agent to prevent decomposition of the particles, as infill
material in an artificial turf system, wherein ground organic material
comprises ground organic hard shells, such as walnut shells, or one of
the group consisting of coconut shells, pecan shells, peanut shells, corn
cobs, and olive stones. The use of particles of a ground organic material
coated with an anti-microbial agent as infill material in the artificial
turf system may further include water retaining particles coated with an
anti-microbial agent, varying between 0 and 60% of the total weight of
the infill. The water retaining particles comprise one of the group
consisting of pozzolon, vermiculite and calcined clay, as infill material
in the artificial turf system. The use of particles of a ground organic
material coated with an anti-microbial agent as infill material in said
artificial turf system may further include synthetic, ecologically-safe
resilient granules coated with said anti-microbial agent preferably
between approximately 20% and 25% by weight to improve shock activation
properties.

[0021]Additional objects, features and advantages of the invention will
become apparent to those skilled in the art upon consideration of the
following detailed description of the preferred embodiments exemplifying
the best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]The appended claims particularly point out and distinctly claim the
subject matter of this invention. The various objects, advantages and
novel features of this invention will be more fully apparent from a
reading of the following detailed description in conjunction with the
accompanying drawings in which like reference numerals refer to like
parts, and in which:

[0023]FIG. 1 is a cross-sectional view of an artificial turf system
comprising an infill according to the present invention.

[0024]FIG. 2 is a cross-sectional view of another embodiment of an
artificial turf having straight and curved yarns surrounded by an infill
according to the present invention.

[0025]FIG. 3 is a flow chart of the process for making infill products
according to the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0026]Referring to FIG. 1, a cross-sectional view of an artificial turf
system 10 comprising an aggregate turf base 12, a backing 14 made of
woven or non-woven material, a pile fabric 16 tufted in the backing 14
and an infill 18 in the space around the filaments of the pile fabric 16
according to the present invention.

[0027]Referring to FIG. 2, a cross-sectional view of another artificial
turf system 20 comprising of a aggregate turf base 21, a backing 22 made
of woven or non-woven sheet material, a pile fabric 28 tufted in the
backing 22, and the infill 18 in the space around the filaments of the
pile fabric 28 which is a resilient granular material. The pile fabric 28
comprises a straight yarns 29 and curled yarns 30 tufted in the backing
22 in alternating stitch lines.

[0028]The backing 22 of the artificial turf system 20 comprises a primary
backing 24 and a secondary backing 26 and it is sufficiently permeable.
If the secondary backing 26 is impermeable, it should have plural holes
(not shown) to allow rainwater to reach drainage means. The primary
backing 24 may be made of one to three layers of woven and/or non-woven
fabrics. Generally these fabrics are made of polypropylene, polyester or
other synthetic materials. While a two-layer structure of the primary
backing 24 is the most common, the preferred construct is three layers
with the outside layers comprised of a woven and fleeced material known
in the trade as "FLW", and the center layer comprised of a dimensionally
stabilizing woven or non-woven material. The total weight of the primary
backing 24 can vary between 3 ounces per square yard and 12 ounces per
square yard, with the preferred total weight at 10 ounces per square
yard. The secondary backing 26 is a polymeric coating, which is formed by
applying a liquid polymer on the primary backing 24. The polymeric
coating is usually of latex of urethane, with urethane being the
preferred type. The coating weight varies between approximately 12 ounces
per square yard and approximately 30 ounces per square yard, with 28
ounces per square yard of urethane being the preferred weight. Many other
types of artificial turfs or artificial turf systems requiring an infill
16, 18 may use the infill of the present invention, including
non-perforated permeable backings, which may or may not use hot-melt
coatings in lieu of urethane and may contain primary backing layers which
are all woven.

[0029]The depth of the infill 18 is between approximately 1/8 inch and
approximately 2.75 inches, with the preferred depth at approximately 1.75
inch. The height of yarn filaments above the infill 18 is between
approximately 1/2 inch and 1.5 inches, with the preferred height at
approximately 3/4 inch.

[0030]Referring to FIG. 3, a flow chart is shown of the process 40 for
making coated infill products according to the present invention. The
infill 18 comprises natural organic particles made by the process of
grinding in step 42 organic hard material, preferably walnut shells
because of their ideal specific gravity which is above 1 to prevent
floating, but under 1.5 to minimize material requirements and related
freight costs. Other hard materials that may be used instead of walnut
shells include coconut shells, pecan shells, peanut shells, corn cobs,
and olive stones. However, the preferred hard organic material is walnut
shell. The grinding may be accomplished by a standard granulator such as
manufactured by Cumberland Engineering Corp. of Attleboro, Mass. or by
standard corrugated nip-roll cracker mill such as manufactured by Armex,
Inc. of Akron, Ohio. All ground walnut shell particles are 100 W coated
with an effective anti-microbial agent in step 44, and the anti-microbial
agent is preferably a spray applied in sufficient quantity to the natural
infill particles as they drop through a circular configuration of
positioned spray nozzles which insures complete and total coating of each
particle of the ground walnut shells or other particles provided for
coating. The anti-microbial agent may be embodied by Aegis Microbe
Shield® manufactured by Aegis Environments of Midland, Mich.

[0031]However, because of the anionic nature of the preferred walnut shell
material, as well as its tendency to vary in porosity, the coverage and
effectiveness of the anti-microbial coating may be inconsistent. In order
to insure the most effective and complete anti-microbial coating, a
pre-coated resin primer may be applied and dried before application of
the anti-microbial agent. The pre-coating equipment may be embodied by a
tumble applicator feeding to a fluid-bed dryer, known in the art, but any
continuous method of application and subsequent drying may be used. The
resin pre-coat material may be obtained from Aegis Environments of
Midland, Mich.

[0032]The coated infill after step 44 may be packaged in step 46. The
anti-microbial agent protects against and prevents the growth of
bacteria, fungi, and mold. It is non-toxic, hypoallergenic,
non-sensitizing and non-irritating to human skin because the microbe
killing mechanism is mechanical, rather than by chemical toxicity, it
does not wash-off nor is it consumed or distillated in the execution of
its protection. The infill particles have a sieve-size ranging between 8
and 50, with preferable ranges of 18-40 or 14-30. Other coating
application methods may be employed as long as the application is
sufficient to render the entirety of particles lethal to microorganisms
and, therefore, resistant to decomposition as actuated by microorganisms.

[0033]In step 48, which is option A, water retaining particles are added
to the organic infill particles ranging between 0 and 60% of the total
weight of the mixture depending on the predetermined need for evaporative
cooling as determined by the climatic location of the surface
installation. In step 44 the mixture from step 48, which includes organic
particles and water retaining particles, has all particles coated with
the anti-microbial agent. The resulting coated infill mixture then may be
packaged for distribution at step 46. Preferably, the option A coated
infill at step 48 comprises a mixture of 1% pozzolon and 99% ground
walnut shells. The water retaining particles of the infill in step 48 may
alternatively contain up to 60% by volume of a moisture modifier such as
vermiculite and calcined clay. The coated infill after step 46 may be
interspersed among the filaments of the pile fabrics 16 and 28 in FIG. 1
and FIG. 2.

[0034]Still referring to FIG. 3, in step 50, another embodiment of the
infill, option B, is provided by adding to the mixture from step 48 a
proportion of synthetic, ecologically-safe resilient materials or
granules to improve shock attenuation (lower G-max) properties of the
infill mixture, when installed in artificial turf. These resilient
materials may include ethylene-propylene diene monomer(EPDM), other
thermoplastic elastomers or any resilient inorganic or organic material
that is not ecologically harmful. The percentage of resilient granules
may be between 0 and 75%, by weight, but preferably between approximately
20% and 25%. After the resilient granules are added to the infill mixture
in step 50, all particles, which includes organic particles, water
retaining particles and resilient granules, are coated with the
anti-microbial agent in step 44. At step 46, the coated infill mixture is
packaged for distribution.

[0035]Option C comprises adding to the ground organic shells from step 42
a proportion of the synthetic, ecologically-safe resilient materials or
granules, such as EPDM or other thermoplastic elastomers, in step 50 to
improve shock attenuation (lower G-max) properties of the resulting
infill mixture when installed in artificial turf. After the resilient
granules are added to the infill mixture in step 50, all particles and
granules, which include the ground organic shell particles and the
resilient granules, are completely coated with the anti-microbial agent
in step 44. Again at step 46, the coated infill mixture from step 44 is
packaged for distribution.

[0036]The coated infill after step 46 is used in applications where it is
infused (infilled) into an artificial turf product at an infill
installation site in a specified weight and depth. The coated infill is
used in athletic fields, landscaping, play areas (safety turf) and in
other artificial turf applications wherein it may be referred to as an
artificial grass, synthetic grass, synthetic turf, false grass etc. The
coated infill including all particles or granules contains no synthetic
chemicals, and therefore, contains no polycyclic aromatic hydrocarbons
(PAHs), no butylated hydroxyanisole (known carcinogens found in ambient
ground or cryogenically ground recycled-tire-rubber), no silica-sand or
sand or any other particulate known to cause respiratory irritation.
Therefore, the infill according to the invention eliminates exposure to
carcinogens, respiratory exposure to toxic or irritant particulate from
rubber dust or silica-sand, ingestion of toxic chemicals by children, as
well as run-off contamination of an aquifer by infill materials.

[0037]It will also be recognized by those skilled in the art that, while
the invention has been described above in terms of preferred embodiments,
it is not limited thereto. Various features and aspects of the above
described invention may be used individually or jointly. Further,
although the invention has been described in the context of its
implementation in a particular environment, and for particular
applications, those skilled in the art will recognize that its usefulness
is not limited thereto and that the present invention can be beneficially
utilized in any number of environments and implementations where it is
desirable to use infill in an artificial turf. Accordingly, the claims
set forth below should be construed in view of the full breadth and
spirit of the invention as disclosed herein.